Some known breech assemblies that guide a breech of a firearm include DE 103 49 160 B3, which is assigned to the assignee of the present patent. DE 103 49 160 B3 describes a weapon housing or component having a hollow body profile that accommodates different weapon components. The weapon housing or component includes a rail (e.g., a slide rail) having a cross-sectional profile that engages in a corresponding groove of a breech element. The rail may be a roller rail that guides the breech element.
DE 43 45 591 B4, assigned to the assignee of the present patent, describes a self-loading grenade launcher having a breech head that includes a centrally located curved lever catch. The lever catch can be a roller rotatable about a vertical axis. To control the supply of ammunition to the weapon via a belt fed conveyor, the roller runs and/or is positioned in a curved control groove of a curved lever. To lead and/or guide the recoil action of the weapon along an axis, a pass rod is mounted in a steel block that extends through the casing and/or housing of the grenade launcher. Rearward axial movement of the pass rod causes and/or guides the weapon recoil. U.S. Pat. No. 3,563,132 describes a curved lever with a control rail that extends between two pin rollers on a breech head.
DE 1678508 B describes a gas operated loading mechanism with a breech actuatable using a gas piston. A breech head and breech base each include laterally extending control legs or protrusions that slide in corresponding grooves of the weapon housing or casing. To advance a belt-feed mechanism when the breech returns from recoil via a gear wheel of the firearm, the breech base includes a roller that enters a curved groove on the belt-feed mechanism.
DE 197 26 032 A1 describes a breech system for a MKM 88 firearm having a gas-operated loading mechanism. The loading mechanism includes a lateral cam and control tunnel or portion positioned on a breech base. To reduce slow-down friction of the breech head, the cam may prevent rotation of the breech head control latch. A breech sliding nose guides the movement of individual elements of the breech assembly. The weapon housing or casing may include lateral sliding rails in which the breech assembly and/or unit is mounted and/or positioned.
DE 38 35 556 A1 describes a direct-pull breech system for firearms. To enable rectilinear guidance of the breech, the firearm includes two runners. CH 51 131 A describes a direct-pull breech system with locking lugs that include inclined locking surfaces.